In a case where a product is manufactured by forming a pattern on a front surface or each surface of a substrate such as a semiconductor wafer, a glass substrate or a printed circuit board, a substrate transfer apparatus transferring the substrate is employed. The substrate transfer apparatus is used in, for example, a plating process, an etching process, a cleaning process or the like.
Also, some substrate transfer apparatuses transfer a substrate while supporting both surfaces of the substrate. Such a substrate transfer apparatus is applied to a cleaning apparatus, which sprays the substrate with a process liquid ejected from a spray nozzle, an etching apparatus and the like (refer to FIGS. 1 and 2).
FIG. 1 is a plan view of a substrate transfer apparatus, and FIG. 2 is a view of the substrate transfer apparatus seen in the direction of A shown in FIG. 1. In FIG. 1, B depicts a transfer direction of a substrate 102 (hereafter referred to as a “transfer direction B”). Also, in FIG. 2, D1 and D2 depict clamping regions required for transferring the substrate 102 (hereafter referred to as “clamping regions D1 and D2”), and E a region in which a pattern can be formed (hereafter referred to as a “pattern forming region E”). The clamping regions D1 and D2 refer to regions for the substrate transfer apparatus 100 to support the substrate 102, and no pattern can be formed in the regions.
Referring to FIGS. 1 and 2, the substrate transfer apparatus 100 has a first substrate support transfer member 105-1 and second substrate support transfer member 105-2. The first substrate support transfer member 105-1 has a plurality of substrate support mechanisms 101A provided along the transfer direction B of the substrate 102. The second substrate support transfer member 105-2 has a plurality of substrate support mechanisms 101B provided along the transfer direction B of the substrate 102. The first and second substrate support transfer members 105-1 and 105-2 are disposed in such a way that the substrate support mechanisms 101A are opposed to the substrate support mechanisms 101B.
The substrate support mechanisms 101A each have rotary shafts 103 and 106, an upper roller 104, a lower roller 107 and drive means (not shown) which rotates the rotary shafts 103 and 106.
The rotary shaft 103 is disposed in such a way that a direction perpendicular to the transfer direction B of the substrate 102 forms a predetermined angle α with an axial direction of the rotary shaft 103. The upper roller 104, being a roller which makes contact with a front surface of the substrate 102, is provided on the rotary shaft 103. The upper roller 104 is disposed in such a way that a rotation direction of the upper roller 104 is directed outward with respect to the transfer direction B of the substrate 102. A rotation direction of the upper roller 104 forms a predetermined angle α with the transfer direction B of the substrate 102.
The rotary shaft 106 is provided below the rotary shaft 103, and the direction perpendicular to the transfer direction B of the substrate 102 forms a predetermined angle α with an axial direction of the rotary shaft 106.
The lower roller 107 is provided on the rotary shaft 106 in such a way as to oppose the upper roller 104 in a thickness direction of the substrate 102. A rotation direction of the lower roller 107 is directed outward with respect to the transfer direction B of the substrate 102. The rotation direction of the lower roller 107 forms a predetermined angle α with the transfer direction B of the substrate 102. The lower roller 107, being a roller which makes contact with a back surface 102B of the substrate 102, transfers the substrate 102 in conjunction with the upper roller 104. Also, the substrate support mechanisms 101B are configured in the same way as the substrate support mechanisms 101A.
In the thus configured substrate transfer apparatus 100, since the upper roller 104 and the lower roller 107 do not contact with the pattern forming region E of the substrate 102, it is possible to prevent a microscopic pattern formed on the substrate 102 from being damaged by the upper roller 104 and the lower roller 107.
Also, as the rotation direction of the upper roller 104 and the lower roller 107 is directed outward with respect to the transfer direction B of the substrate 102, a tension is generated in a direction directed outwardly of the substrate 102 from the center of the substrate 102, enabling the substrate 102 to be prevented from deflecting (See Japanese Patent Unexamined Publication JP-A-2005-508816).
However, in the above-described substrate transfer apparatus 100, because a tension of the upper and lower rollers 104, 107 provided in the substrate support mechanism 101A and a tension of the upper and lower rollers 104, 107 provided in the substrate support mechanism 101B, the substrate 102 is transferred in a meandering manner. Thus, there are required to increase a width of the clamping regions D1 and D2 in order to prevent the substrate 102 from falling off.
Therefore, there is a problem in that this reduces an area of the pattern forming regions E in which a product is manufactured. In the substrate transfer apparatus 100, in order to transfer the substrate 102 without causing it to fall, the clamping regions D1 and D2 are each required to have a width of 15 mm or more.
When the predetermined angle α is reduced for reducing the clamping regions D1 and D2, the tension is reduced and it leads to a falling of the substrate 102. Accordingly, an employment of ceramics or metal as a material of the upper roller 104 and the lower roller 107 can be considered in order to firmly support the substrate 102. However, in the event that ceramics or metal is used as the material of the upper roller 104 and the lower roller 107, there is a problem in that damage occurs on a surface of the substrate 102 which contacts with the upper roller 104 and the lower roller 107.
Also, the longer a length of the substrate transfer apparatus 100 is, the more significantly the substrate 102 meanders, so that it becomes difficult to adjust the predetermined angle α. Furthermore, as the predetermined angle α is increased, the substrate 102 meanders more significantly, so that the substrate 102 runs off and falls off from the upper roller 104 and the lower roller 107. Also, as the predetermined angle α is reduced, the tension is reduced, therefore a central portion of the substrate 102 deflects, and the substrate 102 runs off and falls off from the upper roller 104 and the lower roller 107.